This is a replacement air bladder cell for the Drive Medical 14029M alternating pressure mattress. The bladder cell is the portion of the mattress that holds the air. There are 2 types of air bladders available: with or without laser holes. The bladder cells with the laser holes make up the middle 9 cells of the mattress, and they let out the small amount of air necessary to alternate the mattress's pressure. The bladder cells without the laser holes do not release any air, and they make up the other 11 bladder cells on the mattress. Each bladder cell has an 8" height.